As is the case prior to every primary season, pundits are speculating about the possibility that a candidate could win a major party's presidential nomination in 2008 without getting a majority of the votes in the primaries and caucuses. They believe this could happen if there are more than two candidates who garner strong support during a party's nominating process. In this case, 35-40% of the vote could be enough to win most of the primaries and caucuses. But would it be enough to win the nomination?
On the Democratic side, it is highly unlikely because delegates are generally awarded on a percentage-of-the-vote basis during the primaries and caucuses. For example, a candidate winning with 40% of the vote would be awarded 40% of the available delegates. But to win the nomination, a candidate must get at least one more than 50% of the total delegates available. Obviously, constantly winning with 35-40% of the total in each contest will not get a candidate to this required goal.
Now, with the Democrats, not all of the delegates are awarded during the primaries and caucuses. Some of delegates are set aside as "super delegates." These delegates are made up of high-ranking party "regulars" and elected officials like members of the Senate, members of House of Representatives, governors, lieutenant governors, members of state legislatures, etc. Their votes are not dependent upon how their respective states voted in the primaries and caucuses. They are officially uncommitted and can vote for whomever they wish at the nominating convention. However, a candidate who only gets 40% of delegates awarded during the primaries and caucuses would be hard pressed to win the nomination, even if he or she were to get the votes of 80% of all the super delegates.
On the Republican side, it's a different story because the primary and caucus delegates are generally awarded on a winner-take-all basis. For example, if John McCain won the South Carolina Primary, he would get all of that state's convention delegates, even if he only got 35% of the vote. In addition, the Republican Party does not employ the use of super delegates — all of its convention delegates are awarded during its nominating contests. Therefore, it's plausible that a GOP presidential candidate could win the nomination without getting a majority of the votes in the primaries and caucuses.